Organic light-emitting diodes (OLEDs) have attracted significant attention because of their great potential for making next-generation flat panel displays, i.e., active-matrix organic light-emitting diode displays (AMOLEDs). The standard OLEDs consist of a transparent electrode, organic layers and a metallic reflective electrode, which experience a strong ambient light reflection and a reduced contrast of displays operating under sunlight, mandating a circular polarizer. Other approaches, such as black cathodes, have been proposed. However, all these designs absorb and waste the incident ambient light and a significant amount of light emitted by the OLEDs. In addition, AMOLEDs today are typically integrated with a touch panel in front of the AMOLED in many applications such as cellular phones, personal digital assistants (PDAs), computer displays and touch tablets. The light output from the OLEDs is further reduced by the touch panel. Altogether, the AMOLED display system is complex and costly, and exhibits relatively low efficiency and wastes a large amount of energy.